beat up vs knock out

beat up and knock out both are verbs.

Word	Noun	Adjective	Verb	Adverb
beat up	No	No	Yes	No
knock out	No	No	Yes	No

As verbs, knock out is a hyponym of beat up; that is, knock out is a word with a more specific, narrower meaning than beat up:

beat up: give a beating to; subject to a beating, either as a punishment or as an act of aggression
knock out: knock unconscious or senseless

beat up (verb)	knock out (verb)
gather	destroy or break forcefully
give a beating to; subject to a beating, either as a punishment or as an act of aggression	eliminate
	empty (as of tobacco) by knocking out
	knock unconscious or senseless
	overwhelm with admiration